From: Tejun Heo <tj@kernel.org>
To: sashiko-reviews@lists.linux.dev
Cc: sched-ext@lists.linux.dev
Subject: Re: [PATCH 5/5] sched_ext: Gate scx_bpf_cidperf_set() behind a new SCX_CAP_PERF
Date: Fri, 24 Jul 2026 09:07:49 -1000 [thread overview]
Message-ID: <ab7fd0a02dcef6bb60ffee9bb0c1f8ba@kernel.org> (raw)
In-Reply-To: <20260724184605.EB6641F01559@smtp.kernel.org>
On Fri, Jul 24, 2026 at 06:46:05PM +0000, sashiko-bot@kernel.org wrote:
> [Severity: High]
> Does unconditionally passing SCX_CAP_PERF break backward compatibility on
> older kernels?
>
> If scx_qmap is loaded on a pre-gate kernel where SCX_CAP_PERF is not part of
> __SCX_CAP_ALL, won't the kernel's scx_bpf_sub_grant() and scx_bpf_sub_revoke()
> reject the unknown cap bit?
It would, but that's fine. The sub-scheduler caps interface is still
going through initial development and there is no cross-version
compatibility commitment for it yet. The in-tree schedulers track the
in-tree kernel for these interfaces.
Thanks.
--
tejun
next prev parent reply other threads:[~2026-07-24 19:07 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-24 18:21 [PATCHSET sched_ext/for-7.3] sched_ext: Follow-up fixes and missing cap enforcement Tejun Heo
2026-07-24 18:21 ` [PATCH 1/5] tools/sched_ext: Don't restart over a pending exit request Tejun Heo
2026-07-24 18:21 ` [PATCH 2/5] sched_ext: Gate local DSQ reenq on baseline cid access Tejun Heo
2026-07-24 18:21 ` [PATCH 3/5] sched_ext: Count kicks denied for lacking " Tejun Heo
2026-07-24 18:21 ` [PATCH 4/5] sched_ext: Factor out scx_cpuperf_set() Tejun Heo
2026-07-24 18:30 ` sashiko-bot
2026-07-24 19:07 ` Tejun Heo
2026-07-24 18:21 ` [PATCH 5/5] sched_ext: Gate scx_bpf_cidperf_set() behind a new SCX_CAP_PERF Tejun Heo
2026-07-24 18:46 ` sashiko-bot
2026-07-24 19:07 ` Tejun Heo [this message]
-- strict thread matches above, loose matches on Subject: below --
2026-07-24 19:16 [PATCHSET v2 sched_ext/for-7.3] sched_ext: Follow-up fixes and missing cap enforcement Tejun Heo
2026-07-24 19:16 ` [PATCH 5/5] sched_ext: Gate scx_bpf_cidperf_set() behind a new SCX_CAP_PERF Tejun Heo
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